Umm any way to do it old school? Spicing wires using federal signal...For mine I use the core system with ginnwire.com harness.
Do you have other lights that you are trying to sync with? For standalone flashers, I like the Whelen ULF44. It has standard flash patterns, and an override pattern option. It also syncs with other Whelen smart lightheads. Diode isolation is best, but if your racetrack is on with your park lights, it wont flash using diode isolation. You may want to use relays to break the signal so that the racetrack will flash whether or not your OEM lights are already on.